Variable capacity pump



March 18, 1941. JQY V 2,235,579

VARIABLE cAPAcI'w Puur Filed sept. 7, 1938 3 'sheets-sheet 1 mezz/03. I A f JMW/NU@ l A@ 4- MM. da@

` March 18, 1941. J, F, JQY 2,235,579

VARIABLE CAPACIT' PUIP Filed Sept. 7, 19158 3 Sheets-'Sheet 2 J. F. JOY

I VARI-ABLE CAPACITY PUMP March 18,1941.

5 Sheets-.Sheet 5 Filed sept. 7, 1958 mm.. N

fw y i, W

5 me fig Patented Mar. 18, 1941 PATENT oFFicE A2,235,579 VARIABLE CAPACITY PUMP Joseph F. Joy, Claremont, N. H., assignor to Sullivan Machin Massachusetts Application September 7,

ery Company, a

lcorporation of 1938, Serial No. 228,811

11 claims; (ci. ros- 161) This invention relates to. variable capacity pumps, and more particularly, but not exclusively, to improvements in variable capacity pumps of vthat character which is es pecially designed for use as a driving element of a. variable speed hydraulicpower transmission.

An object of the present invention is to provide an improved variable capacity pumpA having improved means for varying the pump displacei ment. Another object is to providean improved variable capacity pump of the reciprocating piston type having improved means for varying the piston stroke, to vary the displacement of the pump. A further object is to provide an improved i variable stroke pump having improved stroke yvarying means for the pump piston designed so that the capacity of the pump may be varied smoothly from zero to amaximum capacity. A still further object is to provide an improved l variable -stroke actuating means for a pump `piston embodying means adjustable at will to vary the piston stroke. Still another object is to provide an improved stroke varying means operatively connected to the piston for effecting re- 5 ciprocation of the latter and having means for varying the angular relation of certain of the elements thereof to vary the action of the stroke eecting means. Yet another object is to provide an improved valve mechanism for such a pump. These yand other objects and advantages of the invention twill, however, hereinafter more fully appear. v

in the accompanying drawings there are shown for purposes of illustration one form and a modication which the invention may assume in practice. v

In these drawings- Fig. l1 is atop plan view of anl illustrative em- Lo bodiment of the` improved pump, with the top portion of the casing omitted and a part broken away. J l

Fig. 2 is a side elevational view of the pump shown. in Fig. 1, with a portion of the casing l5 structure shown in vertical section. f v

Fig. 3 is av'iew in longitudinall vertical section taken substantially on line-3 4 of Fig. 1.

Fig. 4 is a longitudinally extending horizontal sectional view taken substantially on line I-4 of Fig. 5 is a cross sectional view taken substantir, ally'on line 5-5 of Fig. 3.

Fig. 6- is a fragmentary sectional view taken in the plane of Fig. 4, showing parts in a different 55 position. l

vhaving an integral Fig. 7 is a cross sectional view taken substantially on line 1`I of Fig. 3.

Fig'. 8 is a view similar to Fig. 3, showing a' modified form of construction.

Fig. 9 is a horizontal sectional view, taken sub- 5 stantially on line 9-9 of Fig. 8, with parts in elevation.

Fig. 10 is a cross sectional view lli-I0 of Fig. 8. v In both the illustrative embodiment of the in- 10 ventioi shown in Figs. 1 to '7, inclusive, and the modiication shown in Figs. 8, 9 and 10, the improved pump, generally designated I, is of the variable `capacity type especially designed for use as the driving element of a variable speed power `transmission means, and is particularly adapted for use with a variable speed hydraulic motor vfor supplying fluid under pressure in variable quantities to the latter.l It will be understood, however, that the improved pump is of general application and may be associated with various forms of hydraulic power transmissions.

As shown in Figs. 1 to 7, inclusive, the improved pump I is arranged in a chamber 2 formed in a casing 3, and this casing chamber is adapted to taken on' line 'contain a fluid, preferably a liquid such as oil.

comprises a rotary cylindric body Il drive shaft 5 adapted to be driven from any suitable source of power and journaled within the casing chamber by a ball bearing 6 supported by a bearing bracket 1 integral With the casing 3. The rotary pump body is The .pump

journaledat its opposite end on an alined ball bearing 8 supported by a stub shaft 9 iixed within the outer casing wall, the latter being preferably in the formof a detachable cover plate I0. It-will thus be seen that the pump is rotatable as a unit within the casing about a horizontalaxis, when `the drive shaft is driven. The pump body 4 is formed with a transverse cylinder bore 40 Il arranged withr its longitudinal axis at right angles to the axis oi?v rotation of the pump body and containing a reciprocable pump piston I2 of the double-acting type having piston head por tions at its opposite ends. closely tting the walls of the cylinder'bore. Fixed in a stationary position with respect 'to the casing 3, as by a pin I3 secured to the bearing bracket V, is a valve block I4 having opposed arcuate grooves or slots I5 and I6, the former connected to an intake pipe I1 50 and the-latter to a discharge pipe I8'. The intake pipe I1 is submerged in the oillwithin :the casing I chamber 2, as shown' in Fig. 3,.and is provided with a suitable strainer I9 for preventing entry of dirt to the intake pipe. 'I'he plane end face 20 55 tively movable abutting surfaces,

ofthe rotary pump body 4 has a close running t with an abutting plane end face 2I of the stationary valve block I4, and, if desired, any suitable sealing means, such as a sealing ring, may be provided to prevent leakage between the rela- Ihe rotary pump body 4 has passages 22 and 23 respectively communicating with the remote ends of the cylinder bore IIas shown in Figs. 4 and 6, and communicable through ports 24 and 25, respectively, with the supply and exhaust grooves I5 and I6 in the valve block. As the pump body 4 rotates relative to the stationary valve block I4, the ports 24 and 25 move'suc'cessively into communication with the supply and exhaust grooves,

and as the piston I2 reciprocates within its bore,

fluid is drawn in from the intake groove and thereafter discharged through the discharge groove, in an obvious manner.

Now referring to the improved means for actuating the piston and for varying the piston stroke, it Will be observed that the piston I2 has rack teeth 26 formed thereon and meshing with the teeth of a gear segment 21 formed integral with a p ivoted block 28. This pivoted block 28 is mounted on a transverse pivot pin 29 arranged at right angles to the axis of rotation of the pump body and supported at its ends within bushings 30 supported within laterally spaced projections 3| integral with the pump body. The pivoted block is arranged between these spaced projections, as shown in Fig. 5. It therefore will always, when oscillated about its pivot, `swing in the diametric planes in which the piston moves. 'Ihe actuating means for oscillating the pivoted block to `cause piston reciprocation may now be described. Arranged in right angular relation to the pin 29 and extending through alined bores 32 and\33 formed in the pin 29 and pivoted block 28, respectively, is a pin 34 pivotally connected at its ends 'at 35 to a ring bearing 36. The ring bearing 36 is preferably composed of two mating parts to facilitate assembly, and the two parts thereof cooperate Ato provide an annular flange 31 rotatably engaged in an annular groove 38 provided by a trunnion-providing element 39 and a cooperating retaining annulus 40 secured, as `by screws 4I, to the element 39. The element 39, .as viewed in Fig. 5, is itself generally in the form of an Vannulus and is pivotally mounted at 42 through trunnions supported in upper and lower bearing brackets 43, herein preferably supported by the `detachable cover plate I0 of the casing. 'I'he element 39 is swingable horizontally about a vertical axis within its pivotal bearing mountings and has an integral projecting lever 44 engaged in a transverse rect-angular slot 45 formed in a'cpxig'ol shaft 46. This control shaft is slidably mounted at 41 in a bearing boss 48 formed integral with the bearing bracket 1, and its outer portion is threaded at 49 for threaded engagement with a-nut 50. This nut is rotatably mounted in alined ball thrust bearings supported within a bearing bracket 52, herein preferably formed integralv with the detachable cover plate III. A hand wheel 53 integral with the nutl 60 is provided for manually rotating the latter to eect axial adjustment of the control shaft 46. Rotation of -,the control shaft during such axial adjustment is pre'vented by the lever 44 engaging the walls of the slot 45 in the control shaft. The cooperating threads on the nut and control shaft are self-locking and positively lock the control shaft in its adjusted position. The rectangular-ly related axes of the pins constitute pivotal axes,

since the ring bearing and gear-segment-block rock about the axes of the pins as the pumpparts revolve and the trunnion element 39 is tilted.

In the modifiedvconstruction disclosed in Figs. 8, 9 and 10, the pump cylinder and piston structure and the means for effecting a variable piston stroke are essentially the same as those described above (like parts-being designated by like reference characters), with the exception that the drive shaft for the cylindric pump body is located at the same end vof the pump as the stroke-varying-means for the pump piston, and the pump valve mechanism is arranged at the end of the pump opposite from the drive shaft. In this construction, the cylindric pump body is indicated vat 55 and the drive shaft at 56, and the valve mechanism is generally designated 51. The bore II containing the reciprocatory pump piston I2 is fitted with a liner sleeve 58 having flanged ends and held imposition by threaded plugsv 59 engaging the flanged liner ends, as

shown in Fig. 9. The cylindric pump body is' journaled for rotation within the casing chamber 2 by a ball bearing 60 supporting the shaft 55 and a ball bearing 6I supporting a cylindric valve member 62 secured, as by( a key, within a bore 63 in the pump body, these bearings being,

suitably supported within the end walls of the casing. The member 62 is' formed with a conically-shaped bore 64 receiving a tapered valve plug 65 xed to the detachable cover plate of the outer casing wall. This valve plug has a tight running flt with the walls of the bore 64, and the space at the inner end of the valve plug is vented by a passage 66 and an annular groove 61 on the liner sleeve communicating with the interior of the casing chamber. The valve plug has transverse grooves 68 and 69 communicating with passages and 1I respectively, and the passage 10 is connected to a supply pipe 12 submerged within the liquid in the casing chamber. while the passage 1I is connected to a discharge pipe 13. The member 62 has radial ports 14 and communicating with the valve plug [bore in the same transverse planes as the groov s 68 and 69 and communicating respectively wit passages 16 and 11 in the pump body. 'The passages 16, and 11 have ports communicatingwith the remote ends of the cylinder bore lli) and the liner sleeve has perforations in registry Kwith these ports. As the pump body and theA valve member 62 rotate relative to the stationary valve plug 65,the ports 14 and 15 in the valve mem,- ber 62 move successively into communication with the supply and exhaust grooves-68 and 69, and as the piston I2 is reciprocated, liquid ls drawn in from the supply groove and thereafter discharged through the discharge groove, in an obvious manner. It will be evident that the tight running t between-the tapered valve plug and its bore substantially eliminates leakage between the parts. Otherwise, this embodiment of the invention is the same as that above described.

The mode v`of, operation of the embodiment of the improved variable stroke pump disclosed in Figs. 1 'to 7, inclusive, wil1 be clearly apparent from the4 description given. When the drive shaft 5 is driven in any suitable manner -and the'parts are in the neutral position shown in Fig/.fI 4, the pump body 4 is rotated, rotating therewith as a unit the parts 29, 36 of the stroke varying means, and, due to the fact that the pin -34 will rotate withits longitudinal axis confined in u lelism and the maximum traced by the axis of starci-:exposition 75' vzontally` about its pivot-al plane, as shown in .connection between the a transverse plane perpendicular to the axis oi centrally located position within the cylinder bore, and no liquid displacement from the pump will occur. Whenit is desired to eect liquid displacement, the operator may adjust the nut hand wheel 53, thereby to move the control shaft 46 axially, and swing the element 39 horimounting to vary the angular relation of the plane traced-by the pin 34, with respect to the transverse vertical plane including the axisv of dent that the axis ofthe pin 36 and the laxis of/the piston I2 will be continuously maintained in the same planewith each other but that their relation to each other will vary between paralangle .equal in angularity to the dihedral anglebetween the planes the piston I2 and by the kaxis ofthe pin 34, and in view of the relation of the vblock 28Lto the be eiected a r'eclprocatory motion of the piston I2 in its cylinder, the piston being in central position in its cylinder whenv the axis of the pin 34 andthe axis of the piston I2are parallel to each other. By varying the angular position oi the element 39 about its pivot, the piston stroke may be varied, consequently varying the dis placement of the pump. When the trunnion element 39 is tilted out of a transverse vertical- Fig. 6, and the pump parts are rotating about the axis of the shaft upon driving by the latter, the ring bearing 36 revolves in theannular groove.36 in the relatively stationary element 39 and as a result the ring bearing 36 has a slight rocking movement about the axis of the pivot pin 34 relative to the block 28. Simultaneously the ring bearing 36 and block 28 have a rocking movement aboutthe axis of the pivot pin 29 and as a result the gear segment 21 swings back and yforth to effect reciprocation of the pump piston. The rectangularly related axes of the pivot pinsprovlde a universal gear segment and the trunnion element 39 so that when the element 3,9 is tilted into diierent positions, the axis of swinging movement of the gear segment 21 is varied, resulting in a corresponding variation in the reciprocatory strokes of the pump piston. When the parts are in the full line position shown in Fig. 6, the pump piston I2 is in its maximum stroke position, and it will be evident that the element 39 may be swung intoV any desired` intermediate position between that shown in Fig. 6 and that shown in Fig. 4, to vary the piston stroke from a -inaximum to zero. As above mentioned, as the pump body 4 rotates relative to the stationary valve block I4, the ports 24, 25 are brought successively into communioation with the supply and discharge grooves I5 and I6. so that iluid is drawn into the cylinder bore'from the supply groove and 'discharged from the cylinder bore through the discharge groove. When theelement 39 is swung about its pivotal mounting from the position shown in Fig. 6 to the dotted line position shown in that iigure, the liquid tlow through the pump is'reversed so thatliquid is dischargedirojm 'the groove I6 to the groove I5, at'thattime.' The mode of operation will be very clear when itis' borne in mind that the pistonV I2 will bein mid.: each time the-pin v34 is 'alined with the pivotal axesof. the element 39,' a relathe pin 29.v 'It will be eviring bearing 36 there will,l

tive position assumed "twice in each cylinder member rotation irrespective of the position of the lever 44. -The mode 'of operation of the'modied construction disclosed in Figs. 8, 9 and 10 is essentially the same as that above described in that when the drive shaft 56 is driven in any suitable manner and the parts are in their neutral position shown in Fig. 9, thepump body is rotated, rotating therewith asa unit the parts of the stroke-varying-means,and, due to the position of the parts, rotationof the pump body will not causel reciprocation ofk the pump piston, and the piston will remain stationary in its midway position within the cylinder bore, and no liquid displacement from the pump will occur. When it is desired to effect liquid displacement, the operator may adjust the stroke-varying-mechanism, in the manner described above,-thereby to yswing theV element 39 horizontally about its pivotal mounting to vary the angular relation of the plane traced by the pin 34, with respect to the transverse vertical plane including the axis of the pin 29, andas a result, as above explained, the piston is reciprocated back andlforth within the cylinder bore. It will again` be evident that by varying the angular position' of the element 39 about its pivot, the piston stroke may be varied, consequently varying the pump displacement all in the manner described above.. The liquid is drawn into the pump cylinder from the pipe 12 into the passage 10 and "groove 68 and thence to the cylinder-entering-ports and is discharged from. the cylinder through.' the groove 69, passage 1I and pipe 13. Any leakage of liquid .past the surfaces of the plug and the that anf improved variable stroke pump is pro-'f4 vided having improved means for varying the stroke of the pump piston. It will further be noted that by the provision of the piston reciprocating means disclosed, the capacity of the pump may be varied by imperceptible degrees from zero toa maximum capacity in an extremely simple manner. Furthermore, by the provisionzof the improved piston reciprocating means,'the piston l stroke may not only be varied'in an extremely simple manner, but the parts are also of a rugged and durable construction well adapted to withstand the demands of service. It will also be evident that by thev provision of the improved' valve mechanism, leakage between the relatively rotatable valve parts is reduced to a minimum. Other, uses and advantages of the improved variable stroke pump will `be clearly apparent to those skilled in the art.

While there are in this application specica1ly described one form and a mcdiiication which thev invention may assume in practice, it will be 1nderstood that this .form and modiiication of the same are shown for purposes of illustration and lthat the invention may be further modified and4 embodied'in various other forms without departing from its vspiritor the scope of theap pended claims. Y

What I. claim asnew and desire to secure byv Letters Patentis:

1. In afpump, the combination -of a` rotary s Dump body' having pump piston reciprocable zithin -said cylinder a transverse cylinder bore, a,

'les

means including D iston reciprocating elements rotatable with said-pump body and operatively connected to said piston for reciprocating the latter as said pump body rotates. said piston reciprocating elements comprising a rack formed on said piston and a pivotally mounted gear segment having its teeth meshed with the rack teeth and means for swinging said gear segment about its pivot.

2. In a variable stroke pump,'the combination of a rotary pump body having a transverse cylinder bore, a pump piston reciprocable within said cylinder bore, means for rotating said pump body, means including piston reciprocating'elements rotatable with said pump body and operatively connected to said piston for reciprocating the latter as said pump body rotates, saidy piston reciprocating elements comprising a rack formed on said piston and a pivotally mounted gear segment having its teeth meshed with the rack teeth and means for swinging said gear segment about its pivot, and means ilorl varying the range of swinging movement of said gear segment. Y

3. In a variable -stroke pump, the combination of a rotary pump body having a transverse cylinder bore, a pump piston reciprocable within said cylinder bore, means for rotating said pump body, Ameans including elements rotatable ,with said pump body and operatively connected to said piston for reciprocating the latter as said pump body rotates, said piston reciprocating elements comprising a rack formed on said piston, a swingable gear segment having its teeth meshed with the rack teeth, means for pivotally mounting said gear segment on the pump body, a rotatable ring bearing pivotally connected to said gear segment on an axis arranged at right angles to said pivotal axis of said gear segment, and means for varying the range of swinging movement of said gear segment comprising trunnion means within which`said ring bearing is rotatable mounted for pivotal movement and swingable about its pivot for tilting said ring bearing. l

4. In a variable stroke pump, the combination of a rotary pump body having a transverse cylinder bore, a pump piston reciprocable within said cylinder bore, means for rotating said pump body, means including elements rotatable' with said 4pump body and operatively connected to said piston for reciprocating the latter as said pump body rotates, said piston reciprocating elements comprising a rack formed on said piston, a pivotally mounted gear segment having its teeth meshed with the rack teeth, and means for varying the range of swinging movement of said gear segment including an element having a pivotal connection with said gear segment on an axis at right angles to the pivotal axis of said gear segment.

5. In a variable stroke pump, the combination of a rotary pump body having a cylinder bore arranged with its longitudinal axis lying in a plane perpendicular to the axis of rotation oi?A the pump body, a pump pistonreciprocable in said cylinder bore, means for rotating said pump body, means including elements rotatable with said pump body and operatively connected to said piston for reciprocating the latter as said said piston and swingableto effect piston reciprocation, apivotal mounting for said swingable A bore, means for rotating said pump body, and

member on said pump body, and means for varying the range of swinging movement of said swingable member including a pivoted element having. a pivotal connection with said swingable member on an axis at right angles to the pivotal axis of said swingable member, the pivotal axes of said swingable member and said pivoted element being disposed at right angles to the axis of rotation of said pump body.

6. In a variable stroke pump, the combination of a rotary puinp body having a cylinder bore arranged with its longitudinal axis lying in a plane perpendicular to the axis of rotation of the pump body, a pump piston reciprocable in said' cylinder bore, means for rotating said pump body,v means including elements rotatable with said pump body and operatively connected to said piston for reciprocating the latter as said pump body rotates, said piston reciprocating means comprising a swingable member engaging said piston and swingable to effect piston reciprocation, a pivotal mounting for said swingable member on said pump body, and means for varying the range of swinging movement of said swingable member including an element having a pivotal connection with said swingable member on an axis at right angles to the pivotal axis of said swingable member and a pivoted trunnion operatively connected to said pivoted element and within which the latter is rotatably mounted, the pivotal axes of said swingable member and said trunnion being disposed at right angles to the axis of rotation of said pump body.

7. In a variable stroke pump, the combination l of a rotary pump body having a cylinder bore arranged with its longitudinal axis lying in a plane perpendicular to ,the axis of rotation of the pump body, a pump piston reciprocable in said cylinder bore, means for rotating said pump body, means including elements rotatable with said pump body and operatively connected to said piston for reciprocating the latter as said pump body rotates, said piston reciprocating means comprising a swingable member engaging said piston and swingable to eiect piston reciprocation, a pivotal mounting for said swingable member on said pump body, and means for varying the range of swinging movement of said swingable member including an element having a pivotal connection with said swingable member on an axis at right angles to the pivotal axis of said swingable member and a pivoted trunnion operatively connected to said pivoted element and within which the latter is rotatably mounted, the pivotal axes of said swingable member and said trunnion being disposed at right angles to the axis oi.' rotation of said pump body, and means operable at will for adjusting said trunnion about its pivot to vary thev angular relation of said rotatably mounted element and i'or locking said trunnion in its adjusted positions.

8. 'In a pump, the combination of a rotary pump body having a cylinder bore arranged with its longitudinal axislying in a plane perpendicular to the axis of rotation of the pump body,

a pump `piston reciprocable within said cylinder.

bore, means for rotating said pump body, means including elements rotatable with said pump body and operatively connected to said piston for reciprocating the latter as saidpump body rotates, said pistonreciprocating elements comprising a swingable member pivotally mounted on said pump body on an axis at right angles to the axis of rotation of said pump body and engaging said piston, and means for eiecting swinging movepump body rotates, said piston reciprocating element of said swingable member back and forth as said pump body rotates to effect piston reciprocation comprising a rotatable member having a pivotal connection'with said swingable.

member on an axis at right angles to the axis of pivotal movement of said swingable member. Y

9. In a variable stroke pump, the combination of a rotary pump body hafving a cylinder bore `ar ranged with its longitudinal axis lying in a plane perpendicular to the axis of rotation of lthe pump body, a pump piston reciprocable Within said cylinder bore, means for rotating said pump body, means including elements rotatable with said pump body and operatively connected to said piston for reciprocating the latter as said pump body rotates, said piston reciprocating elements comprising a swingable member pivotally mounted on said pump body on an axisat right angles to the axis of rotation of said pump body jand engaging said piston, means for effecting Aswinging movement of said swingable member back and forth as said pump body rotates to eiect piston reciprocation comprising a rotatable member h aving a pivotal connection with said swingable member on an axis at right angles to the axis of pivotal movement of said 'swingable member, and means for adjusting said rotatablel member to vary the range of pivotal movement of said rswingable member comprising a pivotally mounted member on which said rotatable member is mounted andA means for adjusting said pivotally mounted member into diierent angular positions about its pivot.

10. In a variable stroke pump, a rotary pump body having a cylinder bore arranged with its longitudinal axis lying/in a plane perpendicular to the axis of rotation of the pump body, a pump .piston reciprooable within saidcylinder bore, lmeans for rotating the pump body, means including piston reciprocatingv elements rotatable with said pump body and operatively connected to said piston for reciprocating `the latter as said ment and said pivotally mounted element, and' means for tilting said tiltable element into different positions about its pivot to vary the range of swinging movement of said pivotally mounted element, therebyto vary the piston stroke.

11. In a variable stroke pump, 4a rotary pump body havingI a cylinder` bore arranged with its longitudinal axis lying in a plane perpendicular to the axis of rotation of the pump body, a pump piston reciprocable 'within said cylinder bore,

means for rotating the pump bodyme'ans i'pcluding piston reciprocating elementsrotatable with said pump body and operatively connected to said piston for reciprocating Vthe latter as said pump body rotates, said piston reciprocating elements comprising a piston reciprocating element pivotally mounted on said pump body, a tiltable element pivotally mounted on a Arelatively iixedl axis and relative towhich said pump bodyis ro- Y tatable, the pivotal axes of said lpiston recipro-v cating element andsaid tiltable element-being arranged at right angles to the axis of rotation of the pump body, an operative connection bey -I tween said tiltable element and said pivotally f mounted element including an element having a pivotal connection with said pivotally Vmounted element on an axis at right angles to the pivotal axis of said pivotally mounted element, and means for tilting said tiltable element about its pivot to vary the range of swinging movement of said pivotally mounted element-,thereby to vary the piston stroke. I

' JOSEPH F. JOY. 

